Hi im new to the forum and new to trials. I want to start trials because before chistmas I bought a £800 mountain bike and been once with it and my dad does not want to go any more but I love balancing and muccing around on it. my question is what size bike do I need I am 5"3 and 14? the second question is what are the bst websites to get the bikes from want a bike quit cheap no maore than abou £300 a bit less maybe thanks in advance